Field of the Invention
The present invention relates to a method of sending multimedia data and, more particularly, to a method of sending a large amount of multimedia data.
Discussion of the Related Art
Multimedia service provided by sending video and audio content is the most popular service in Internet-based services. For high-quality multimedia service, the size of video and audio content is increased.
Various types of methods for sending a large amount of multimedia content are being proposed. One of the methods is a client-server transfer scheme. The client-server transfer method is problematic in that service quality is severely deteriorated if the number of users is greater than the number of users handled by a server due to a load of the server increased as the number of users is increased. A task for improving performance of a server for solving such a problem requires great expense.
Another method is an IP multicast scheme. IP multicast is a technology for sending the same packet to a plurality of users at once and may be applied to services, such as real-time streaming and a video conference. In the case of Video On Demand (VOD), however, if the IP multicast technology is applied, there is a problem in that quality of service is deteriorated because a delay time taken for many users to start to be provided with service (hereinafter called a “start delay time”) is lengthened because users request the same content at different times.
In addition, a Content Delivery Network (CDN) scheme for copying content to cache servers installed at the lower end of a network close to a user and delivering the content from a cache server to a user when the content is demanded and a P2PVoD scheme using a P2P technology when sending video have been proposed.
However, the CDN scheme are problematic in that it may not be applied to small-scale business operators due to a high installation charge and it may have the same problems occurring in the client-server transfer method if users are crowded in a single cache server.
Furthermore, the P2PVoD scheme may reduce a load of a server because video is received from corresponding users if the number of users who watch the same content is many, but has a problem in that the start delay time is lengthened if the number of users is small and playback may be interrupted if a user who provides video departs from a service system.